issue2551413 - Broken MultiLink columns in CSV export

cmeerw found a crash and bug.

While investigating CSV export using names with a multilink field that
doesn't have a label field (name or realname for user class). cmeerw's
patch displays a multilink like messages as "['12', '23']" as when
exporting csv with id. I changes code so this displays as "12;23" to
match the list format output of the other fields in export csv (with
names).

Author: rouilj

CHANGES.txt

@@ -37,6 +37,10 @@ Fixed:
   script. Found/patch by Norbert Schlemmer. (John Rouillard)
 - change some internal classes to use __slots__ for hopefully a small
   performance improvement. (John Rouillard)
+- issue2551413 - Broken MultiLink columns in CSV export. CSV export of
+  a multilink link "messages" that does not have a 'name' property
+  causes a crash. (found/fix by cmeerw; commit and better handling of
+  non-labeled multilink by John Rouillard)
 
 Features:
 

roundup/cgi/actions.py

@@ -1688,14 +1688,17 @@ def fct(arg):
             if isinstance(props[col], hyperdb.Multilink):
                 cname = props[col].classname
                 cclass = self.db.getclass(cname)
-                represent[col] = repr_list(cclass, 'name')
                 if not self.hasPermission(self.permissionType, classname=cname):
                     represent[col] = repr_no_right(cclass, 'name')
                 else:
                     if 'name' in cclass.getprops():
                         represent[col] = repr_list(cclass, 'name')
                     elif cname == 'user':
                         represent[col] = repr_list(cclass, 'realname')
+                    else:
+                        # handle cases like messages which have no
+                        # useful label field issue2551413 
+                        represent[col] = repr_list(cclass, 'id')
             if isinstance(props[col], hyperdb.Link):
                 cname = props[col].classname
                 cclass = self.db.getclass(cname)